Power-transmission device.



No. 841,723. PATBNTED JAN. 22, 1907.

W. T. SEARS. POWER TRANSMISSION DEVICE.

APPLICATION FILED SEPT. 28, 1906.

. I mill/[7m Witnesses j; v I, Inventor W nb Attorney 1 ing at Philadelphia, Philadelphia county,-

- UNITED" ums J TEN 1* OFFICE- WILLARD 'IHOMAS SEARS, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR j TO NILES-BEMENT-POVND COMPANY, QFJERSEY- CITY, NEW JERSEY.

POWER-TRANSMISSION DEVICE.

f To rill whom it may concern: I

Be it known that I, WILLARD THOMAS SEARS, a citizen of the United States, resid- 5 Pennsylvania, have invented certai'n new and useful Improvements in Power-Transmission Devices, of which the following is a specification.

the transmissionof power in which are in- I 5 proved means for guarding against, first, the

volved relatively shifting toothed membersv for changing the rate of motion or the direc-'.

tionof motion or the condition from restto motion, and vice versa, and relates to 1mdifficulties of intermembering the teeth when teeth do not happen to match tooth-spaces;

second, the liability of the transmission ofheavy .work through "teeth but partially en'-' 26 gaged, and, third, the labor of shifting teeth into engagement while they are under the strain ofheavy duty.

" The invention-will be readily understoodfrom the-following description, taken in connection with the ,accompanyingdr'awings, in

Figure 1 is a front elevation' of an apparatus embodying my invention; Fig. 2, a vertical transverse section of a portion of the same,

o illustrating shifting mechanism which may be employedyFiglB, a side elevation of the driving-pulley and one of the centrifugal weights, and Fig. 4 a front elevation of the shifting toothed, member in modified form.

larger gear fast on the driven shaft; 6, a pair of gears fast with each other and splined on 40 the driving-shaft; 7, a shifter engaging the pair ofsplined gears and adapted toslide 1 them so that its component gears may mesh with either of themating gears, respectively, on the driven shaft; 8, a friction-clutch,

4 5 which may be of any desired or suitable ordinary construction; 9, an endwise movable bar to servein engaging and disengaging the clutch; 10, a friction-diskfast on the drivingshaft contiguous to the clutch, the rim of this disk being illustratedasV-shaped in cross- I Specification of Letters Patent. Application filed September 28, 1906. seen 110. 336,584.

Th's invention pertains to apparatus for In the drawings, .1 indicates housing parts 4' 2, the driving-shaft; 3 ,the driven shaft 4, a

gear fast on the'driven shaft; 5, a second but Patented an; 22, 1907.

. to the housing and adapted to 0061)- erate with the friction-disk; 13, a cam-lug earned by clutch-shifting bar 9 and cooperat 1ng with the brake-shoe in such. manner as to apply the latter when the bar is moved somewhat beyond the clutch-releasing position,

jawed clutch serving to illustrate another form of shifting toothed member; I, f

The shifting of the sliding toothed memher and also the operation ofthe frictionclutch may be accomplished in any desired or usual manner, the illustration showing, in Fig; 2 a simple rack-and-pinion arrangement, permitting the two shifting devices to be adjusted independently, the shifter '7 having a i and 14 theslidingmember of an ordinary rack operated by a pinion having a hand-' wheel on its shaft ,'while the clutch-operating bar '9 has a rack operated by a pinion having a handle onfits shaft, which latter shaft is tubular and surrounds \the other shaft, all as clearly understandablefrom Fig. 2. These I details are, however, notherein claimed.- In

Fig; .4 the part '14 will be recognized "as the jawed sliding member of an ordinary jawed clutch commonly employed in'engaging loose gears 0r py ys to or disengaging them r ashaft. a

' Under ordinary conditions, the parts were stationary, the friction-clutchbdng released, for instance, an attempt to slide ear 6 into active osition might be defeats by the'failiire o tooth ends to register with.

tooth-spaces. Something might require to be angularly' adjusted beforethe engagement of the teethcould be effected. Again, if

gears 6 were in rotation, opportunity would present itself for starting the teeth into the tooth-spaces, but-the result would be that the full working strain would. come on the gear-teeth as soon as they were engaged, even to the most trifling extent. .This may result inthe breaking of teeth, and always results in mutilating the ends of the teeth, and considerable force might be required to complete the sliding engagement of the teeth after they had gotten under the strain of full work. These considerations will apply to I most "any power-transmission; system involving a toothed member to be shifted into I and out of engagement with a mating toothed member. v 7

In the present construction assume that a the friction-clutch isreleased, which would quickly and easily and mean that under ordinary conditions the driving-shaft would be at rest; but while the pulley of the friction-clutch is thus released from the driving-shaft the centrifugal weights frictionally engage the interior ofthe friction-disk, which is fast on the driving shaft; and this friction will turn the drivingshaft and the shifting gears after the main power has been cut off. While the gears 6 are thus in rotation they may be shifted into engagement with one of the mating gears, the turning of the sliding gear insuring an opportunity for the proper entry of teeth. As soon as the teeth shall have started into engagement then the sliding ar ceases its rotation, the

The sliding gear may now be shiftedto position of complete engagement While under only trifling tangential strain. After the en-" gagement of teeth has been completed then the friction-clutch may be engaged and full power thrown on. Teeth may thus be safely thrown into and out of engagement regardless of how heavy the powermay be which is to betransmitted through them when in full engagement.

In connection with the system described" shaft is not in motion.

I claim 1. Power-transmission apparatus comprismg a pair of. toothed members, supports for said toothed members, means for shifting one grip of the centrifugal weights not being sufficient to turn the driven shaft.

unison with one of said toothed members,

and a centrifugal weight driven by said rotarydriving part and enga ing said friction.- disk, combined substantia 1y as set forth, whereby one of said toothed members is under the'rotative. influence of the centrifugal weight after the main power is unclutched from it.

2. Power-transmission apparatus comprising a pair of toothed members, supports for said toothed members, means for shifting one of said toothed members into and out of engageir. out with its mate, a rotary driving part loose relative to said members, a frictionc-lutch for causing said rotary driving part to transmit power to the toothed members when 1 engaged, a friction-disk turning positively in umson with one of said toothed members, a centrifugal wei lit driven by said rotary driving part an engaging said friction-disk, a brake-shoe cooperating with said frictiondisk,.and a clutch-operating part cooperating with the brake-shoe and adapted to apply it ,after the friction-clutch is released, combined substantially as set forth.

3. Power-transmission apparatus comprising a member tobe rotated by power selectively'at full power or minor power, a rotary driving part loose relative to said-member, a friction-disk fast with said member, a centrifugal weight carried'by the driving part and. engaging the disk to transmit minor power, and a friction-clutch connected with said 11: ember and driving part for transmitting full. power, combined substantially as set forth, WILLARD THOMAS SEARS.

Witnesses:

WILLIAM BLPIAGE,

SAMUEL C. KANE-- 

